In a drying mechanism for a washing and drying machine, the means for generating heated air is a heating system for heating the air by a heater. In order to reduce energy consumption, developed a heat pump dryer, the use of heat pump system to strengthen the heat recycling. The existing tumble dryer is provided with, only a drying air inlet at the front of a dryer in a drying method of the general drying tube drying method (see FIG. 1), only a drying air inlet at the back of a dryer in the heat pump drying method (see FIG. 2).
Specifically, as shown in FIG. 1, the conventional heating tube clothes drying method is a method in which a heating pipe 1′ and a fan 2′ are provided in the air duct, and the circulation type heating is further provided with a condensing device 3′, the water vapor in the hot and humid air needs to be condensed and drained before the heating; the non-circulating drying air method is that air is heated outside and carried out into the drum, and the hot and humid air is discharged to the outside after the drying (not shown in the Fig). As shown in FIG. 2, the conventional heat pump type clothes dryer is provided with an air circulation passage in which the heater air heated by the condenser 5′ flows through the circulation passage from the rear air inlet of the drum into the drying chamber that loaded with clothes. The moisture-absorbed air taken from the clothes is sent back to the evaporator 6′ by the front air outlet for dehumidification, and the dehumidified air is again heated by the condenser 5′ and fed into the drying chamber.
A Chinese patent application No. 200610146442.2 discloses a washing dryer using a heat pump as a heat source. In particular, it relates to a device for heating air by using a heat source of a condenser in a heat pump system, drying the clothes using an evaporator in the system as a dehumidifying and cooling source. On the rear side of the outer barrel of the washing machine is provided with a hot air inlet, and the front end of the outer barrel of the drum is provided with a hot air outlet, the hot air outlet with an air duct is communicated with the hot air inlet, an evaporator is placed in the air channel near the hot air outlet and set in the air duct near the hot air inlet.
A Chinese patent application No. 201110183197.3 discloses an inner and outer cylinder structure having a drying function washing machine. The inner cylinder is coaxially arranged inside the outer cylinder, and the inner cylinder shaft passes through the rear part of the outer cylinder. The rear part of the outer cylinder is provided with a drying air inlet, and the outer periphery of the drying air inlet between the inner side of the rear part of the outer cylinder and the outer part of the inner part of the inner cylinder is provided with anti-radial air diffusing windshield structure. Wherein the windshield structure is a plurality of ribs which are respectively provided in the inner side of the rear part of the outer cylinder and the outer side of the outer part of the inner cylinder in the circumferential direction and the ribs are on the periphery of the drying air inlet, and The ribs have different radii so that the adjacent ribs on the inner side of the rear portion of the outer cylinder and the outer portions of the rear portion of the inner cylinder are staggered.
Whether drying clothes by the heater or by the heat pump system, the heated air is generally supplied from the rear of the outer drum to the inner drum through the air duct. After the heat exchange with the wet clothes, the humidified air is discharged from the front of the inner drum or condensed to dehumidify and then circulated to dry clothes. Dryers are equipped with only one drying inlet, during the drying process, clothes close to the inlet dry faster, but clothes will shrink for staying in a high temperature for a long time. Clothes far away from the inlet are not easy to dry for a lower temperature, especially one piece with high weight clothing, prone to uneven internal drying under this situation.
A Chinese patent application No. 201110231574.6 discloses washing dryer with a front and a rear double drying air inlets and a control method thereof. The washing dryer includes an outer shell, an outer cylinder arranged inside the outer shell and an inner cylinder rotatable inside the outer cylinder, and a heat pump system for drying clothes. The heat pump system comprises a heat pump air inlet and a heat pump air outlet. The front and rear parts of the outer cylinder are provided with a front drying inlet and a rear drying inlet, respectively, and a drying air outlet is arranged at the top of the outer cylinder. And the drying air outer is communicated with the heat pump air inlet through the inlet air duct, the heat pump air outlet is communicated with the rear drying inlet through an air supply duct, and the second air duct is arranged between the front air inlet and the air supply duct. And a second air duct is arranged between the front drying air inlet and the air supply air duct. The second air duct that in close contact with the outer wall of the outer cylinder is formed integrally with the outer cylinder. The air outlet of the heat pump is controlled by the switching mechanism to be connected with the front drying inlet and/or to the rear drying inlet.
Although the above-described structure discloses two air inlets, it is essentially one air inlet which is controlled by the switching mechanism to select one to intake air. And the front air inlet and outlet are set in the front of the outer cylinder. When choosing the front air inlet, it can not effectively use the intake air to dry clothes, the purpose is to regulate the heat pump compressor efficiency. The two air inlets are arranged at the front and rear ends of the outer cylinder, and the drying of the clothes is uneven no matter which air inlet is selected, and the clothes are seriously damaged.
In view of the foregoing, the present invention is proposed.